ES2452690T3 - Sonar group system - Google Patents

Abstract

An active sonar group (10) for generating sound having a sound pressure level to detect objects in deep waters and at long ranges including: a transmitter group (12) having two or more sound projection transducers arranged along an axis of transmitter group; and a receiver group (14) coupled to said transmitter group, said receiver group having two or more hydrophones (14a, 14b, ..., 14X) arranged along a receiver group axis, the receiver group axis having y the axis of the transmitter group a common axis, characterized in that each transducer (164) is arranged within an acoustic projector (12a, 12b, ..., 12N), each acoustic projector (12a, 12b, 12N) including a projector housing ( 158), a front end plug (162) sealed to the housing and a rear end plug (156) sealed to the housing to form a watertight sealed compartment (160) within which the transducer (164) is located; the diameter and length of the acoustic projector and the diameter and length of the transducer being selected to allow each acoustic projector to generate sound that has a sound pressure level of at least 205 dB re 1μPa at 1 meter and being dimensioned in such a way that said transmitter group has a diameter greater than or equal to 20.32 centimeters, and where said receiving group has a diameter less than or equal to the largest diameter of said transmitting group in such a way that said receiving group and said transmitting group form a single roll-down linear system that can be deployed and retrievable by a unique trawler attached to a boat.

Description

Sonar group system

Field of the Invention

This invention relates in general to a sonar apparatus and in particular to sonar groups for underwater use.

Background of the invention

A ship, for example a military ship, can drag a group of sound receiving hydrophones arranged as a passive dragged group. The passive entrained group, in conjunction with sound reception and signal processing electronics, can detect sounds in the water that can indicate, for example, the presence of an enemy submarine.

In other arrangements, the ship can drag both a passive dragged group of sound receiving hydrophones and also a dragged acoustic projector, which together form a bistatic active sonar system. With this arrangement, the dragged acoustic projector emits sound pulses. Each pulse of sound advances through the water, which collides in objects or targets in the water, which produce echoes. The echoes are received by the entrained group of receiving hydrophones. Therefore, an echo indicates the presence of an underwater object, and the direction from which the echo comes indicates the direction of the underwater object.

In conventional bistatic active sonar systems, the dragged acoustic projector is often deployed and dragged separately from the dragged group of sound receiving hydrophones. A conventional dragged acoustic projector typically includes a sound source mounted within a large rigid drag body, for example in a conventional AN / SQS35 drag body used by the United States Navy. The conventional dragged acoustic projector is large and heavy. For example, the size may be of the order of forty-eight cubic feet and the weight may be of the order of 4000 pounds. The dragged acoustic projector of this type is typically used to detect objects in deep water and long range. Therefore, the dragged acoustic projector is capable of generating sound that has a high level of sound pressure, for example 220 decibels in relation to a microPascal in one meter (also expressed here as dB re 1 μPa in 1 m) in order to allow the system to receive echoes and therefore detect objects in the deep water at long range. This type of bistatic active sonar group is not very suitable for coastal waters that have less depth.

The dragged group of receiving hydrophones is often deployed and retrieved through a hull penetrator below the boat's water line. In contrast, due in part to its size and weight, the dragged acoustic projector is deployed and retrieved above the boat's gift with winch and boom equipment. The large dragged acoustic projector, which requires deployment above the boat's gift, limits secret deployment and recovery. The deployment and recovery of the acoustic projector dragged over the boat's gift can also be unmanageable and dangerous during deployment and recovery at sea.

Conventional bistatic active entrained group systems are configured in such a way that the acoustic projector is operated with equipment separate from the equipment that manages the entrained group of receiving hydrophones. Large handling equipment is needed to deploy and retrieve the dragged acoustic projector. Large handling equipment requires a considerable amount of deck space on a ship. Large handling equipment is undesirable not only because of the deck space it requires, but also because it has a radio target that has a large radar cross section for enemy radar systems.

An active sonar group including a transmitter group and a receiver group coupled to said transmitter group is known as FR 2 822 960, where buoyancy is provided by separate elements between the transmitters. A single group dragged for an active sonar including a transmitter group and a receiver group, which allow deployment and recovery using a single winch, is known from DE 197 43 096, where the transducers are placed in a tube with hollow rings around the transducers so that fluid can pass through it.

Therefore, it would be desirable to provide a system that has a group of receiver hydrophones as well as a dragged acoustic projector from which both can be deployed and retrieved using a single set of handling equipment. It would also be desirable to provide a sonar group that has the series of receiver hydrophones as well as the dragged acoustic projector from which both can be deployed and retrieved through a single boat hull penetrator. It would also be desirable to provide a sonar group that is suitable for operation in coastal waters that have a relatively small depth.

Summary of the Invention

The present invention is defined in the claims, to which reference is now made. The active sonar group has both a receiver group and a transmitter group coupled to a single drag cable. Projectors

Acoustics used in the transmitter group are capable of producing a high level of sound pressure (SPL) while having a small size. The sonar group has a transmitter group and a receiver group to form a single "roll-up" group. The transmitter group has two or more acoustic projectors capable of generating sound and the receiver group has two or more hydrophones capable of receiving sound. The two or more acoustic projectors are arranged on an axis of the transmitter group and the two or more hydrophones are arranged on an axis of the receiver group. The receiving group axis and the transmitting group axis have a common axis, thus forming contiguous line groups, one for transmitting and receiving. The sonar group can be dragged to form a horizontal line group that has both acoustic and hydrophone projectors. With this particular arrangement, acoustic projectors and hydrophones can be deployed and retrieved from a single winch. In a particular embodiment, at least one of the acoustic projectors may include a grooved cylindrical transducer. The cylindrical grooved arrangement allows each of the acoustic projectors to be relatively small and light, therefore, a relatively small winch can be used to deploy and retrieve the sonar group.

One method of detecting underwater objects includes deploying a sonar group from a single winch, including the sonar group both a transmitter group and a receiver group. The transmitter group has two or more acoustic projectors capable of generating sound and the receiver group has two or more hydrophones capable of receiving sound, all arranged on a common axis. The method also includes retrieving the sonar group from the only winch. The deployment and recovery can be by means of a boat hull penetrator or above the boat's gift.

With this particular arrangement, the method allows the deployment and recovery of the sonar group from a single winch. Deployment and recovery can be done in secret with a single boat hull penetrator.

Brief description of the drawings

The foregoing features of the invention as well as the invention itself can be more fully understood from the following detailed description of the drawings, in which:

Figure 1 is a graph of a sonar group system according to the present invention.

Figure 2 is a graph of the sonar group system showing deployment and recovery equipment.

And Figure 3 is a graph depicting a portion of the sonar group system of Figures 1 and 2.

Detailed description of the invention

Referring now to Figure 1, a sonar group system 10 according to the present invention includes a receiving group 14 having one or more hydrophones 14a-14X. The one or more hydrophones 14a-14X are arranged along an axis of the receiving group to form a linear receiving group.

The sonar group system 10 also includes a transmitter group 12 coupled to the receiver group 14 with a separator cable 13. The transmitter group 12 includes one or more acoustic projectors 12a-12N. The one or more acoustic projectors 12a-12N are arranged along an axis of the transmitter group to form a linear transmitter group. The receiver group axis and the transmitter group axis are arranged along a common axis, thus forming a contiguous transmitter / receiver group 15 having both acoustic projectors 12a-12N and hydrophones 14a-14X.

A drag cable 16 couples the transmitter / receiver group 15 to the boat 18. The drag cable 16 provides a mechanical coupling between the ship 18 and the receiver group 14. The drag cable also provides electrical connections between the ship 18 and the group receiver 14, of which some pass through the receiver group 14 to the transmitter group 12. The electrical connections may be cable connections or fiber optic connections or a combination of cable connections and fiber optic connections.

In operation, when it is dragged through the water by the ship 18 at sufficient speed, the transmitter / receiver group 15 maintains a generally horizontal orientation due to hydrodynamic forces operating in the transmitter / receiver group 15. It should be noted that, when the ship 18 turns, the transmitter / receiver group 15 can be curved horizontally according to the turn of the ship, while maintaining a common axis for the transmitter group 12 and the receiver group 14.

In order to generate more hydrodynamic forces to maintain the combination of the most almost horizontal transmitter / receiver group 15, an anchor line 11 can be coupled to the transmitter group 12. The anchor line 11 provides more drag force resistance when it is dragged by the water by the ship 18.

Each of the 12a-12N acoustic projectors generates an acoustic projector beam configuration. Each acoustic projector beam configuration can be substantially omnidirectional, and each acoustic projector can generate sound at a particular frequency, for example a frequency in the range of 300 Hz to 4 kHz. Everybody

12a-12N acoustic projectors can project sound that has the same frequency and the same beam configuration. However, in other embodiments, the projectors selected from the acoustic projectors 12a-12N project sound that has a frequency of less than 300 Hz or greater than 4 kHz. In addition, projectors selected from acoustic projectors 12a-12N may have a different beam configuration. In other embodiments, projectors selected from acoustic projectors 12a-12N project sound at more than one frequency, for example, in a frequency band.

Likewise, each of the hydrophones 14a-14X receives sound with a hydrophonic beam configuration. Each hydrophonic beam configuration can be substantially omnidirectional, and each hydrophone 14a-14X can receive sound in a complete concrete frequency band, for example a frequency band from 300 Hz to 4 kHz. All 14a-14X hydrophones can receive sound within the same frequency band and can have the same beam configuration. However, in other embodiments, hydrophones selected from the 14a14X hydrophones may receive sound within a different frequency band and / or have a different beam configuration from that of other 14a-14X hydrophones. In addition, in other embodiments, hydrophones selected from the 14a14X hydrophones can receive sound in a frequency band that extends below 300 Hz and / or above 4 kHz.

In a particular embodiment, the transmitter / receiver group 15 has six acoustic projectors, of which the acoustic projectors 12a-12N are examples, each spaced 60.96 centimeters from center to center, and the transmitter / receiver group 15 has fifty and four hydrophones, of which 14a-14X hydrophones are examples, each spaced thirty centimeters from center to center. The drag cable 16 in a particular embodiment has a length of five hundred meters. However, in other embodiments, the transmitter / receiver group 15 may have more than six or less than six acoustic projectors and more than fifty-four or less than fifty-four hydrophones. In addition, in other embodiments, the 12a-12N acoustic projectors may be spaced more than 60.96 centimeters or less than 60.96 centimeters. In other embodiments, the transmitter group 12 is modular so that acoustic projectors of the transmitter / receiver group 15 can be added or removed.

Those skilled in the art will appreciate that a series of acoustic projectors, for example acoustic projectors 12a-12N within the transmitter group 12, can be used in combination with transmission beam formation electronics (not shown) to generate a beam configuration Directed transmission (not shown). Such a beam configuration is generally conical and can be directed at a selected angle around the axis of the transmitter group 12. Likewise, it should be appreciated that a group of receiving hydrophones, for example the receiving hydrophones 14a-14X within the receiving group 14, can be used in combination with receiving beam formation electronics (not shown) to generate an addressable receive beam configuration (not shown). Similar to the transmission beam configuration, the reception beam configuration is also generally conical and can be directed at a selected angle around the axis of the receiving group

12. Therefore, the beam configuration of the transmitter group 12 can be pointed in the same direction as the beam configuration of the receiver group 12. This particular arrangement can be used to improve the detection operation of the sonar group system 10. However, in other embodiments, the transmission beam configuration and the reception beam configuration may be arranged at one or more fixed angles, without direction.

Although the transmitter group 12 is represented behind the receiver group 14 relative to the ship 18, in an alternative embodiment, the receiver group 14 may instead be arranged behind the transmitter group 12. In another alternative embodiment, the acoustic projectors 12a-12N and The receiving hydrophones 14a-14X may be intermingled so that the acoustic projectors 12a-12N and the hydrophones 14a-14X are intermingled in any combination in a single linear group.

When it is dragged through the water at sufficient speed by the ship 18, the transmitter / receiver group 15 is in a generally horizontal orientation. Although the transmitter / receiver group 15 is represented in a substantially horizontal orientation, in part due to the hydrodynamic drag resistance generated when the ship 18 drags the transmitter / receiver group 15 through the water, in other arrangements the transmitter / receiver group 15 It can assume a different orientation from the horizontal. For example, if the sonar group system 10 is dragged at lower speeds by the ship 18, or is not dragged by the ship 18, the transmitter / receiver group 15 may assume a different orientation from the horizontal, including the vertical. In other embodiments, the transmitter / receiver group 15 is not coupled to a ship. For example, in other embodiments, the transmitter / receiver group 15 is coupled to a buoy.

With reference now to Figure 2, in which similar elements of Figure 1 are represented with similar reference designations, the sonar group system 10 can be deployed and retrieved by the ship 18. In particular, a single winch 102 can deploy and recovering the sonar group system 10 that has the transmitter / receiver group 15.

The sonar group system 10 can be deployed and retrieved through a single hull penetrator 104. Therefore, the sonar group system 10 can be deployed and secretly retrieved so that those not on board the ship 18 cannot see the deployment and recovery of the sonar 10 group system.

A variety of winch sizes 102 can be used with this invention. In a particular embodiment, the winch 102 may include a drum hub 102a having a diameter, D, less than or equal to fifty centimeters. In another embodiment, the drum hub 102a may have a diameter less than or equal to thirty-eight centimeters. Those skilled in the art will recognize that these are relatively small winches. However, in other embodiments, winches with larger drum hub diameters can be used. A minimum drum hub diameter is selected based on several factors, including, but not limited to, the diameter and length of each of the acoustic projectors 12a-12N. Acoustic projectors 12a-12N are described in more detail in conjunction with Figure 3.

A variety of helmet penetrator sizes 104 can also be used with this invention. In a particular embodiment, the helmet penetrator 104 may have a cross-sectional diameter, d, less than or equal to twenty centimeters. In another embodiment, the helmet penetrator 104 may have a cross-sectional diameter, d, less than or equal to 15.24 centimeters. Those skilled in the art will recognize that these are relatively small diameter hull penetrators for sonar systems deployed from a surface ship. However, in other embodiments, helmet penetrators with larger or smaller cross-sectional diameters can be used. A minimum hull penetrator diameter is selected based on several factors, including, but not limited to, the diameter of each of the acoustic projectors 12a-12N.

Referring now to Figure 3, in which analogous elements of Figures 1 and 2 are represented by similar reference designations, a portion 150 of the transmitter / receiver group 15 (Figure 1) includes a transmitter group 12 having one or more 12a-12N acoustic projectors (figure 1), including the 12N acoustic projector. A section of transmitter group cable 151 couples the acoustic projector 12N to the acoustic projector 12b (Figure 1). Considering the acoustic projector 12N representative of all the indicated acoustic projectors, the acoustic projector 12N includes a rear connector shutter 154 for coupling to the transmitter group cable section 151. The acoustic projector 12a includes a rear end shutter 156, which is sealed with o-rings or similar to a projector housing 158. The projector housing 158 may have a cylindrical shape. A front end plug 162 is also sealed to the projector housing 158 with O-rings or the like and a front connector plug 166 couples the acoustic projector 12N to a separator cable 13. Therefore, the acoustic projector 12N is sealed to provide a water-tight compartment 160. The water-tight compartment 160 can be filled with a gas in some embodiments or it can be filled with acoustically conductive fluid, for example castor oil, in other embodiments. A sound projection transducer 164, also simply referred to herein as a transducer 164, can be disposed within the water-tight compartment 160. The transducer 164 is coupled to the separator cable 13 with cables 168, which pass through the separator cable 13 .

The acoustic projector 12N is coupled to the separator cable 13, which couples the transmitter group 12 to the receiver group 14. The separator cable 13 is coupled to the receiver group 14 with a waterproof connector 170.

The receiving group 14 (Figure 1) has the one or more hydrophones 14a-14X (Figure 1), including the hydrophone 14a. In a particular embodiment, the receiving group may be composed of a tube 172 in which the one or more hydrophones 14a-14X are arranged (Figure 1). The tube 172 can be filled with a fluid, for example castor oil.

The transmitter group cable 151, the separator cable 13, and the receiver group 14 may include fiber optic couplings that carry transmission signals to the acoustic projectors 12a-12N (Figure 1) and reception signals of the hydrophones 14a-14X (Figure 1). In other embodiments, the transmitter group cable 151, the separator cable 13, and the receiver group 14 include cable conductors. In other embodiments, the transmitter group cable 151, the separator cable 13, and the receiver group 14 include both cable conductors and fiber optic couplings.

The transducer 164 may be a slotted cylindrical transducer 164, which is adapted to generate sound from the acoustic projector 12N having a sound pressure level of at least 205 decibels relative to a microPascal and a meter (also written here as dB re 1 μPa at 1 m). However, it should be appreciated that other types of transducers 164 known to those skilled in the art can also be used, and the invention is not limited only to grooved cylindrical transducers. In addition, the 12N acoustic projector can generate sound that has a sound pressure level higher or lower than 205 dB re μPa at 1 m. In a particular embodiment, the acoustic projector 12N generates an acoustic beam configuration that has an essentially omnidirectional shape. However, in other embodiments, the acoustic projector 12N may have a directional beam configuration.

Because of the desire to be able to deploy and retrieve the transmitter / receiver group 10 of Figure 2 from a single winch (102, Figure 2) having a small hub diameter (D, Figure 2) as described above, it is desirable that the acoustic projectors, for example the acoustic projector 12N, be small, both in diameter and in length.

In a particular embodiment, the acoustic projector has a diameter of 15.24 centimeters, a length of thirty-eight centimeters, and transducer 164 is a cylindrical grooved transducer having a diameter of ten centimeters and a length of twenty centimeters. With this particular arrangement, the 12N acoustic projector generates sound that has a sound pressure level of at least 205 dB re μPa at 1 m while maintaining a small acoustic projector size that can be deployed and retrieved from the winch (102 , figure 2) having a relatively small hub diameter, D (figure 2), as described above. Without

However, in other embodiments the acoustic projector may have a diameter greater than or less than 15.24 centimeters and a length greater than or less than thirty-eight centimeters. In addition, the transducer can have a diameter greater than or less than ten centimeters and a length greater or less than twenty centimeters.

In a particular embodiment, transducer 164 generates sound having a frequency of 3 KHz. However, in 10 other embodiments, transducer 164 may be adapted to generate sound that has a higher frequency.

or less than 3 kHz.

It will be appreciated that the hydrophones, for example the hydrophone 14a, included in the receiving group 14 (Figure 1) may be smaller than the acoustic projectors, for example the acoustic projector 12N, which are included in the transmitter group 15 (Figure 1). ). Therefore, the receiving group 14 may have a smaller diameter than the acoustic projector 12N. In a particular embodiment, the receiver group 14 has a larger diameter that is approximately the same as the largest diameter of the acoustic projector 12N. In another particular embodiment, the receiving group 14 has a larger diameter that is approximately half the largest diameter of the acoustic projector 12N. In other embodiments, the receiving group 14 has a larger diameter which is another

20 proportion smaller than the largest diameter of the 12N acoustic projector.

Although the acoustic projectors 12N depicted and described have a transducer 164 within a sealed cavity 160, acoustic projectors having other arrangements are possible in this invention. For example, in other embodiments, acoustic projector 12N includes a transducer 164 in an encapsulated or molded water impermeable body 25. Furthermore, although the receiving group 14 has been represented and described including a tube 172, in other embodiments, the only or more hydrophones, of which the hydrophone 14a is an example, are encapsulated.

or molded separately so that they are impervious to water and are coupled together without the tube

172.

Having described preferred embodiments of the invention, it will now be apparent to those skilled in the art that other embodiments that incorporate their concepts can be used. Therefore, it is indicated that these embodiments should not be limited to the described embodiments, but rather should be limited only by the scope of the appended claims.

Claims (21)

1. An active sonar group (10) to generate sound that has a sound pressure level to detect objects in deep water and long range including: a transmitter group (12) having two or more sound projection transducers arranged along an axis of the transmitter group; Y a receiver group (14) coupled to said transmitter group, said receiver group having two or more hydrophones (14a, 14b, ..., 14X) arranged along an axis of the receiving group, the axis of the receiving group and the axis of transmitter group a common axis, characterized in that Each transducer (164) is disposed within an acoustic projector (12a, 12b,…, 12N), each acoustic projector (12a, 12 b, 12N) including a projector housing (158), a front end shutter (162) sealed to the housing and a rear end plug (156) sealed to the housing to form a sealed waterproof compartment (160) within which the transducer (164) is located; selecting the diameter and length of the acoustic projector and the diameter and length of the transducer to allow each acoustic projector to generate sound having a sound pressure level of at least 205 dB re 1 μPa at 1 meter and being sized in such a way that said transmitter group has a diameter greater than or equal to 20.32 centimeters, and where said receiver group has a diameter less than or equal to the largest diameter of said transmitter group in such a way that said receiving group and said transmitting group form a single linear roll-up system that can be deployed and recoverable by a single towing device coupled to a ship.

2.

 The sonar group of claim 1, wherein the transmitter group axis and the receiver group axis are substantially horizontal.

3.

The sonar group of claim 1, wherein the only dragging device has a drum hub diameter of less than or equal to fifty centimeters.

Four.

The sonar group of claim 1, wherein the only dragging device has a drum hub diameter less than or equal to thirty-eight centimeters.

5.

The sonar group of claim 1, wherein said receiver group and said transmitter group are adapted to be deployed and retrieved through a single ship hull penetrator.

6.

 The sonar group of claim 5, wherein the only boat hull penetrator has a smaller diameter less than or equal to twenty centimeters.

7.

 The sonar group of claim 5, wherein the only boat hull penetrator has a smaller diameter less than or equal to 15.24 centimeters.

8.

The sonar group of claim 1, wherein said receiver group and said transmitter group are adapted to be deployed and retrieved above the boat's gift.

9.

The sonar group of claim 1, wherein at least one of the two or more acoustic projectors has a transmission beam configuration that is essentially omnidirectional.

10.

 The sonar group of claim 1, wherein at least one of the two or more acoustic projectors includes a grooved cylindrical transducer.

eleven.

 The sonar group of claim 1, wherein said recipient group has a diameter less than or equal to half the largest diameter of said transmitter group.

12.

 The sonar group of claim 1, wherein said transmitter group has a larger diameter less than or equal to 15.24 centimeters.

13.

 The sonar group of claim 12, wherein said receiving group has a diameter less than or equal to half the largest diameter of said transmitter group.

14.

 The sonar group of claim 1, wherein the two or more acoustic projectors are modular such that they can be added and alternatively removed from the transmitter group to provide an expandable transmitter group.

fifteen.

 The sonar group of claim 14, wherein the transmitter group has a sound pressure level proportional to the

number of acoustic projectors.

16.

 The sonar group of claim 1, wherein said transmitter group is adapted to transmit sound in the

frequency range from 300 Hz to 4 kHz. 5 17. The sonar group of claim 1, wherein said transmitter group is adapted to provide at least one dirigible acoustic transmission beam. 18. The sonar group of claim 1, wherein said receiver group is adapted to provide at least one addressable acoustic reception beam. 19. A method to detect underwater objects, including: deploying an active sonar group according to any one of claims 1 to 18 of a single relatively small dragging device 15 having a drum hub diameter less than or equal to fifty centimeters, the dragging apparatus being coupled to a ship; Y retrieve the sonar group with the only relatively small drag device. 20. The method of claim 19, wherein the transmitting group axis and the receiving group axis are substantially horizontal. 21. The method of claim 19, wherein the only dragging device has a smaller drum hub diameter or equal to thirty eight centimeters. 25 22. The method of claim 19, wherein deployment and recovery include: Pass the sonar group through a boat hull penetrator. 23. The method of claim 19, wherein deployment and recovery include: passing the sonar group over a boat's gift.